Effectiveness of Extracorporeal Life Support for Patients With Cardiogenic Shock Due To Intractable Arrhythmic Storm:

Extracorporeal membrane oxygenation for patients with electrical storm or refractory ventricular arrhythmias: Management and outcomes

Patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are at high risk for ventricular arrhythmias due to derangements in myocardial perfusion, hemodynamics, and heightened catecholamine states. Existing data on the management and outcomes of patients with electrical storm or refractory ventricular tachycardia/fibrillation (VT/VF) treated with VA-ECMO are primarily derived from retrospective observational studies. Typical survival rates are in the range of 40-50%, with 15-20% of patients undergoing VT ablation and 30-40% of patients requiring advanced heart failure therapies (cardiac transplant or durable left ventricular assist device). Similarly, there is a paucity of published data on VT/VF management for patients whilst on VA-ECMO as it is largely extrapolated from patients with electrical storm. Although many of the treatment principles (identifying reversible causes, anti-arrhythmic drugs, VT ablation, and reduction of adrenergic tone) are translatable, several aspects require special consideration when managing VT/VF in the VA-ECMO patient population. Among carefully selected patients on VA-ECMO who underwent VT ablation, reported recurrence rates were ∼30% and a sizeable proportion of them (30-40%) required advanced heart failure therapy as an exit strategy. As well, there are specific issues which require consideration for patients on VA-ECMO who undergo VT ablation such as vascular access, ECMO access site complications, and bleeding due to systemic anticoagulation. Optimal management of VT/VF in this patient population requires ongoing reassessment and dialogue among electrophysiology, heart failure, and critical care specialists. Additional research is needed in order to better inform the care of this very high-risk patient population.

Ventricular arrhythmias in acute heart failure: a clinical consensus statement of the Association for Acute CardioVascular Care, the European Heart Rhythm Association, and the Heart Failure Association of the European Society of Cardiology

Patients presenting with or alerting emergency networks due to acute heart failure (AHF) form a diverse group with a plethora of symptoms, risks, comorbidities, and aetiologies. During AHF, there is an increased risk of destabilizing the functional substrate and modulatory adding to the risk of ventricular arrhythmias (VAs) already created by the structural substrate. New VAs during AHF have previously identified patients with higher intra-hospital and 60-day morbidity and mortality. Risk stratification and criteria/best time point for coronary intervention and implantable cardioverter defibrillator implantation, however, are still controversial topics in this difficult clinical setting. The characteristics and logistics of pre-hospital emergency medicine, as well as the density of centres capable of treating AHF and VAs, differ massively throughout Europe. Scientific guidelines provide clear recommendations for the management of arrhythmias in patients with chronic heart failure. However, the incidence, significance, and management of arrhythmias in patients with AHF have been less studied. This consensus paper aimed to address the identification and treatment of VAs that complicate the course of patients who have AHF, including cardiogenic shock.

ECMO for drug-refractory electrical storm without a reversible trigger: a retrospective multicentric observational study

AIMS

Drug-refractory electrical storm (ES) is a life-threatening medical emergency. We describe the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in drug-refractory ES without a reversible trigger, for which specific guideline recommendations are still lacking.

METHODS AND RESULTS

Retrospective observational study in four Iberian centres on the indications, treatment, complications, and outcome of drug-refractory ES not associated with acute coronary syndromes, decompensated heart failure, drug toxicity, electrolyte disturbances, endocrine emergencies, concomitant acute illness with fever, or poor compliance with anti-arrhythmic drugs, requiring VA-ECMO for circulatory support. Thirty-four (6%) out of 552 patients with VA-ECMO for cardiogenic shock were included [71% men; 57 (44-62) years], 65% underwent cardiopulmonary resuscitation before VA-ECMO implantation, and 26% during cannulation. Left ventricular unloading during VA-ECMO was used in 8 (24%) patients: 3 (9%) with intraaortic balloon pump, 3 (9%) with LV vent, and 2 (6%) with Impella. Thirty (88%) had structural heart disease and 8 (24%) had an implantable cardioverter-defibrillator. The drug-refractory ES was mostly due to monomorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) (59%), isolated monomorphic VT (26%), polymorphic VT (9%), or VF (6%). Thirty-one (91%) required deep sedation, 44% overdrive pacing, 36% catheter ablation, and 26% acute autonomic modulation. The main complications were nosocomial infection (47%), bleeding (24%), and limb ischaemia (21%). Eighteen (53%) were weaned from VA-ECMO, and 29% had heart transplantation. Twenty-seven (79%) survived to hospital discharge (48 (33-82) days). Non-survivors were older [62 (58-67) vs. 54 (43-58); P < 0.01] and had a higher first rhythm disorder-to-ECMO interval [0 (0-2) vs. 2 (1-11) days; P = 0.02]. Seven (20%) had rehospitalization during follow-up [29 (12-48) months], with ES recurrence in 6%.

CONCLUSIONS

VA-ECMO bridged drug-refractory ES without a reversible trigger with a high success rate. This required prolonged hospital stays and coordination between the ECMO centre, the electrophysiology laboratory, and the heart transplant programme.

A Refractory Electrical Storm after Acute Myocardial Infarction: The Role of Temporary Ventricular Overdrive Pacing as a Bridge to ICD Implantation

An electrical storm (ES) is defined as the presence of at least three episodes of sustained ventricular tachycardia or ventricular fibrillation within 24 h. This patient had a previously known arterial hypertension, type II diabetes mellitus, and chronic kidney disease and has presented to the Emergency Department (ED) with symptoms of retrosternal chest pain lasting for several hours prior. The initial 12-lead electrocardiogram revealed ST segment elevation in the anterior leads (V1-V6). Emergent coronary angiography revealed an acute occlusion of the proximal left anterior descending artery (pLAD) and percutaneous coronary intervention was performed with successful implantation of one drug-eluting stent in the pLAD. On day 8 of hospitalization, the patient developed a refractory ES for which he received 50 DC shocks and did not respond to multiple lines of antiarrhythmic medications. Due to a failure of medical therapy, we decided to implant a temporary pacemaker and initiate ventricular overdrive pacing (VOP) that was successful in terminating ES. Following electrical stabilization, the patient underwent a successful ICD implantation. This case demonstrates that VOP can contribute to hemodynamic and electrical stabilization of a patient that suffers from refractory ES and this treatment modality might serve as a temporary bridge to ICD implantation.

Heart transplantation as a rescue strategy for patients with refractory electrical storm

AIMS

Heart transplantation (HT) can be proposed as a therapeutic strategy for patients with severe refractory electrical storm (ES). Data in the literature are scarce and based on case reports. We aimed at determining the characteristics and survival of patients transplanted for refractory ES.

METHODS AND RESULTS

Patients registered on HT waiting list during the following days after ES and eventually transplanted, from 2010 to 2021, were retrospectively included in 11 French centres. The primary endpoint was in-hospital mortality. Forty-five patients were included [82% men; 55.0 (47.8-59.3) years old; 42.2% and 26.7% non-ischaemic dilated or ischaemic cardiomyopathies, respectively]. Among them, 42 (93.3%) received amiodarone, 29 received (64.4%) beta blockers, 19 (42.2%) required deep sedation, 22 had (48.9%) mechanical circulatory support, and 9 (20.0%) had radiofrequency catheter ablation. Twenty-two patients (62%) were in cardiogenic shock. Inscription on wait list and transplantation occurred 3.0 (1.0-5.0) days and 9.0 (4.0-14.0) days after ES onset, respectively. After transplantation, 20 patients (44.4%) needed immediate haemodynamic support by extracorporeal membrane oxygenation (ECMO). In-hospital mortality rate was 28.9%. Predictors of in-hospital mortality were serum creatinine/urea levels, need for immediate post-operative ECMO support, post-operative complications, and surgical re-interventions. One-year survival was 68.9%.

CONCLUSION

Electrical storm is a rare indication of HT but may be lifesaving in those patients presenting intractable arrhythmias despite usual care. Most patients can be safely discharged from hospital, although post-operative mortality remains substantial in this context of emergency transplantation. Larger studies are warranted to precisely determine those patients at higher risk of in-hospital mortality.

Impella Versus VA-ECMO for Patients with Cardiogenic Shock: Comprehensive Systematic Literature Review and Meta-Analyses

Impella and VA-ECMO are two possible therapeutic courses for the treatment of patients with cardiogenic shock (CS). The study aims to perform a systematic literature review and meta-analyses of a comprehensive set of clinical and socio-economic outcomes observed when using Impella or VA-ECMO with patients under CS. A systematic literature review was performed in Medline, and Web of Science databases on 21 February 2022. Nonoverlapping studies with adult patients supported for CS with Impella or VA-ECMO were searched. Study designs including RCTs, observational studies, and economic evaluations were considered. Data on patient characteristics, type of support, and outcomes were extracted. Additionally, meta-analyses were performed on the most relevant and recurring outcomes, and results shown using forest plots. A total of 102 studies were included, 57% on Impella, 43% on VA-ECMO. The most common outcomes investigated were mortality/survival, duration of support, and bleeding. Ischemic stroke was lower in patients treated with Impella compared to the VA-ECMO population, with statistically significant difference. Socio-economic outcomes including quality of life or resource use were not reported in any study. The study highlighted areas where further data collection is needed to clarify the value of complex, new technologies in the treatment of CS that will enable comparative assessments focusing both on the health impact on patient outcomes and on the financial burden for government budgets. Future studies need to fill the gap to comply with recent regulatory updates at the European and national levels.

Association Between Shock Etiology and 5-Year Outcomes After Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND

Outcomes of patients requiring venoarterial extracorporeal membrane oxygenation (VA-ECMO) vary greatly by etiology, but large studies that incorporate the spectrum of shock supported with ECMO are rare.

OBJECTIVES

The purpose of this study was to describe the etiology-related outcome of patients with shock supported with peripheral VA-ECMO.

METHODS

All consecutive adults with peripheral VA-ECMO between January 2015 and August 2018 at Pitié-Salpêtrière Hospital (Paris, France) were included in this retrospective observational study. The indication for VA-ECMO was cardiogenic shock. Rates of hospital death and neurological, renal, and pulmonary complications were evaluated according to etiology.

RESULTS

Among 1,253 patients, hospital and 5-year survival rates were, respectively, 73.3% and 57.3% for primary graft failure, 58.6% and 54.0% for drug overdose, 53.2% and 45.3% for dilated cardiomyopathy, 51.6% and 50.0% for arrhythmic storm, 46.8% and 38.3% for massive pulmonary embolism, 44.4% and 42.4% for sepsis-induced cardiogenic shock, 37.9% and 32.9% for fulminant myocarditis, 37.3% and 31.5% for acute myocardial infarction, 34.6% and 33.3% for postcardiotomy excluding primary graft failure, 25.7% and 22.8% for other/unknown etiology, and 11.1% and 0.0% for refractory vasoplegia shock. Renal failure requiring hemodialysis developed in 50.0%, neurological complications in 16.0%, and hydrostatic pulmonary edema in 9.0%.

CONCLUSIONS

Although the outcome differs depending on etiology, this difference is related more to the severity of the situation associated with the cause rather than the cause of the shock per se. Survival to 5 years varied by cause, which may reflect the natural course of the chronic disease and illustrates the need for long-term follow-up.

Urgent catheter ablation in Japanese patients with mechanical circulatory supports suffering from refractory ventricular electrical storm

BACKGROUND

Therapeutic strategy using catheter ablation for ventricular tachyarrhythmias (VTAs) electrical storms in patients dependent on percutaneous mechanical circulatory support (MCS) has not yet been established.

METHODS

We reviewed the patients with or without requiring MCS who received urgent VTAs ablation in our institute between January 2020 and May 2022. Electrophysiological and clinical outcomes were compared between those with and without requiring MCS.

RESULTS

Twenty procedures (16 patients, median 76 years, 13 males) were included. Six procedures using MCS underwent ablations and the other 14 procedures were performed without MCS. Although VTAs cycle lengths were not significantly different between the two groups, the incidence of hemodynamic stability was significantly higher in MCS group than in those without (83 % vs. 29 %, p = 0.024). Temporary MCS were explanted in all patients following the successful ablation, whereas the complication rates were higher in patients requiring MCS (67 % vs. 0 %, p = 0.001). Cumulative incidences of cardiovascular death and appropriate therapy of implantable cardioverter defibrillator within 90 days following the procedures were not significantly different between the two groups (p = 0.071 and p = 0.063, respectively).

CONCLUSION

Urgent ablation might be a feasible bail out option for those dependent on MCS suffering from VTAs, although physicians should be on high alert for device-related bleeding.

Management of hemodynamically stable wide QRS complex tachycardia in patients with implantable cardioverter defibrillators

Management of hemodynamically stable, incessant wide QRS complex tachycardia (WCT) in patients who already have an implantable cardioverter defibrillator (ICD) is challenging. First-line treatment is performed by medical staff who have no knowledge on programmed ICD therapy settings and there is always some concern for unexpected ICD shock. In these patients, a structured approach is necessary from presentation to therapy. The present review provides a systematic approach in four distinct phases to guide any physician involved in the management of these patients: PHASE I: assessment of hemodynamic status and use of the magnet to temporarily suspend ICD therapies, especially shocks; identification of possible arrhythmia triggers; risk stratification in case of electrical storm (ES).

PHASE II

The preparation phase includes reversal of potential arrhythmia "triggers", mild patient sedation, and patient monitoring for therapy delivery. Based on resource availability and competences, the most adequate therapeutic approach is chosen. This choice depends on whether a device specialist is readily available or not. In the case of ES in a "high-risk" patient an accelerated patient management protocol is advocated, which considers urgent ventricular tachycardia transcatheter ablation with or without mechanical cardiocirculatory support.

PHASE III

Therapeutic phase is based on the use of intravenous anti-arrhythmic drugs mostly indicated in this clinical context are presented. Device interrogation is very important in this phase when sustained monomorphic VT diagnosis is confirmed, then ICD ATP algorithms, based on underlying VT cycle length, are proposed. In high-risk patients with intractable ES, intensive patient management considers MCS and transcatheter ablation.

PHASE IV

The patient is hospitalized for further diagnostics and management aimed at preventing arrhythmia recurrences.

Predictors and outcome of electrical storm-induced cardiogenic shock

AIM

Limited information is available about the short- and long-term outcomes in electrical storm (ES)-induced cardiogenic shock (CS) and its predictors.

METHODS AND RESULTS

This is a retrospective, single-centre cohort study of consecutive patients with ES admitted to the Cardiac Intensive Care Unit between 2015 and 2020. The proportion of ES patients who developed CS was adjudicated, and clinical predictors of in-hospital ventricular arrhythmia (VA)-related mortality and 1-year all-cause mortality were investigated. Of the 214 patients with ES, 33.6% developed CS. Left-ventricular ejection fraction, admission lactate, absence of an implantable cardioverter defibrillator, and admission central venous pressure were independently associated with development of CS (P < 0.03 for all). Based on these variables, a FLIC score was developed (https://riskcalc.org/FLICscore/) to predict ES-induced CS [area under the curve (AUC) = 0.949, with AUC = 0.954 in a validation cohort, both P < 0.001]. Patients who developed CS had a 11.3-fold [95% confidence interval (CI) 2.7-12.8] increased odds for in-hospital VA-related mortality and 9.4-fold (95% CI 4.0-22.4) increased odds for in-hospital all-cause mortality. A FLIC score above 0.62 was associated with a 6.2- and 5.8-fold increased odds for respectively similar endpoints. Patients with ES-induced CS received more treatment modalities to manage the ES (4.5 ± 1.8 vs. 2.3 ± 1.2, P < 0.001) and had longer length of stay [14 (8-27) vs. 8 (5-13), P < 0.001] than patients without CS. Interestingly, if patients with ES-induced CS survived to discharge, their outcomes were similar to those without CS at 1 year.

CONCLUSION

Cardiogenic shock in ES is a frequent and potentially life-threatening complication with high short-term mortality. A novel risk score could identify patient at risk, generating a potential for early risk-based interventions.

Mechanical circulatory support in ventricular arrhythmias

In atrial and ventricular tachyarrhythmias, reduced time for ventricular filling and loss of atrial contribution lead to a significant reduction in cardiac output, resulting in cardiogenic shock. This may also occur during catheter ablation in 11% of overall procedures and is associated with increased mortality. Managing cardiogenic shock and (supra) ventricular arrhythmias is particularly challenging. Inotropic support may exacerbate tachyarrhythmias or accelerate heart rate; antiarrhythmic drugs often come with negative inotropic effects, and electrical reconversions may risk worsening circulatory failure or even cardiac arrest. The drop in native cardiac output during an arrhythmic storm can be partly covered by the insertion of percutaneous mechanical circulatory support (MCS) devices guaranteeing end-organ perfusion. This provides physicians a time window of stability to investigate the underlying cause of arrhythmia and allow proper therapeutic interventions (e.g., percutaneous coronary intervention and catheter ablation). Temporary MCS can be used in the case of overt hemodynamic decompensation or as a “preemptive strategy” to avoid circulatory instability during interventional cardiology procedures in high-risk patients. Despite the increasing use of MCS in cardiogenic shock and during catheter ablation procedures, the recommendation level is still low, considering the lack of large observational studies and randomized clinical trials. Therefore, the evidence on the timing and the kinds of MCS devices has also scarcely been investigated. In the current review, we discuss the available evidence in the literature and gaps in knowledge on the use of MCS devices in the setting of ventricular arrhythmias and arrhythmic storms, including a specific focus on pathophysiology and related therapies.

Recent insights into mechanisms and clinical approaches to electrical storm

Electrical storm, characterized by repetitive ventricular tachycardia/fibrillation (VT/VF) over a short period, is becoming commoner with widespread use of implantable cardioverter-defibrillator (ICD) therapy. Electrical storm, sometimes called "arrhythmic storm" or "VT-storm", is usually a medical emergency requiring hospitalization and expert management, and significantly affects short- and long-term outcomes. This syndrome typically occurs in patients with underlying structural heart disease (ischemic or non-ischemic cardiomyopathy) or inherited channelopathies. Triggers for electrical storm should be sought but are often unidentifiable. Initial management is dictated by the hemodynamic status, while subsequent management typically involves ICD interrogation and reprogramming to reduce recurrent shocks, identification/management of triggers like electrolyte abnormalities, myocardial ischemia, or decompensated heart failure, and antiarrhythmic-drug therapy or catheter ablation. Sympathetic nervous system activation is central to the initiation and maintenance of arrhythmic storm, so autonomic modulation is a cornerstone of management. Sympathetic inhibition can be achieved with medications (particularly beta-adrenoreceptor blockers), deep sedation, or cardiac sympathetic denervation. More definitive management targets the underlying ventricular arrhythmia substrate to terminate and prevent recurrent arrhythmia. Arrhythmia targeting can be achieved with antiarrhythmic medications, catheter ablation or more novel therapies such as stereotactic radiation therapy that targets the arrhythmic substrate. Mechanistic studies point to adrenergic activation and other direct consequences of ICD-shocks in promoting further arrhythmogenesis and hypocontractility. Here, we review the pathophysiologic mechanisms, clinical features, prognosis, and therapeutic options for electrical storm. We also outline a clinical approach to this challenging and complex condition, along with its mechanistic basis.

Use of extracorporeal membrane oxygenation for heart graft dysfunction in adults: incidence, risk factors and outcomes in a multicentric study

Background:

The decision about whether to use venoarterial extracorporeal membrane oxygenation (VA-ECMO) in patients with cardiac graft dysfunction (GD) is usually made on a case-by-case basis and is guided by the team’s experience. We aimed to determine the incidence of VA-ECMO use after heart transplantation (HT), to assess early- and long-term outcomes and to assess risk factors for the need for VA-ECMO and early mortality in these patients.

Methods:

We included adults who underwent heart transplantation at 3 cardiac centres who met the most recent International Society for Heart and Lung Transplantation definition of graft dysfunction (GD) over a 10-year period. Pre-transplant, intraoperative and posttransplant characteristics of the heart recipients as well as donor characteristics were analyzed and compared among recipients with GD treated with and without VA-ECMO.

Results:

There were 135 patients with GD in this study, of whom 66 were treated with VA-ECMO and 69 were not. The mean follow-up averaged 81.2 months (standard deviation 36 mo, range 0–184 mo); follow-up was complete in 100% of patients. The overall incidence of GD (30%) and of VA-ECMO use increased over the study period. We did not identify any predictive pre-transplantation factors for VA-ECMO use, but patients who required VA-ECMO had higher serum lactate levels and higher inotropes doses after HT. The overall survival rates were 83% and 42% at 1 year and 78% and 40% at 5 years among patients who received only medical treatment and those who received VA-ECMO, respectively. Delayed initiation of VA-ECMO and postoperative bleeding were strongly associated with increased in-hospital mortality.

Conclusion:

The incidence of GD increased over the study period, and the need for VA-ECMO among patients with GD remains difficult to predict. In-hospital mortality decreased over time but remained high among patients who required VA-ECMO, especially among patients with delayed initiation of VA-ECMO.

Electrical storm: Prognosis and management

Electrical storm is present when a cluster of ventricular arrhythmias (VAs) occurs within a short time frame. The most widely accepted definition is 3 or more episodes of VA within a 24-h period, although prognostic risk begins to rise when 2 or more events occur within 3months. Electrical storm often presents as a medical emergency in the form of recurrent implantable cardiac defibrillator (ICD) shocks, recurrent syncope in patients with no ICD or low cardiac output symptoms. Management often requires a multimodality approach including ICD management, pharmacologic therapy, catheter ablation and modulations of the autonomic nervous system. In this article, we review the definition, prognosis and management of electrical storm.

Five Hours of Resuscitation With 150 Electrical Shocks and Complete Recovery

Background: Myocardial ischemia may lead to lethal arrhythmias. Treatment of these arrhythmias without addressing the cause of ischemia may be futile. The length of resuscitation is an important parameter for determining when to stop resuscitation but with shockable rhythms and reversible cause of the cardiac arrest, the decision to terminate resuscitation is complex. 

Case Summary: A patient with a three-month history of shortness of breath with effort developed pulseless ventricular tachycardia (VT) at the early stages of a stress test. In coronary angiography, a critical lesion in the right coronary artery (RCA) was observed and treated with two stents. During the procedure and for a total of five hours, the patient had more than 100 separate episodes of VT and ventricular fibrillation (VF) that were treated by 150 defibrillations, artificial ventilation, intra-aortic counter-pulsation balloon insertion, and multiple drugs. One hour after the initial stenting procedure, thrombosis of the RCA was demonstrated and treated successfully with angioplasty. Use of procainamide resolved the arrhythmias and the patient recovered completely without neurological deficit, ejection fraction of 45%, and is asymptomatic at one year following the event.

Discussion: Our case shows that with a revisable cause of cardiac arrest, resuscitation should be directed at maintaining perfusion of essential organs and treating the reversible cause. Without re-opening the RCA, we could not have saved the patient's life. The use of an extracorporeal membrane oxygenator, if available, should be considered in similar cases. Finally, the quality of cardiopulmonary resuscitation determines the neurological outcome regardless of the length of resuscitation, as was evident in our patient who recovered completely.

Cardiac Arrhythmias in Survivors of Sudden Cardiac Death Requiring Impella Assist Device Therapy

In this retrospective single-center trial, we analyze 109 consecutive patients (female: 27.5%, median age: 69 years, median left ventricular ejection fraction: 20%) who survived sudden cardiac death (SCD) and needed hemodynamic support from an Impella assist device between 2008 and 2018. Rhythm monitoring is investigated in this population and associations with hospital survival are analyzed. Hospital mortality is high, at 83.5%. Diverse cardiac arrhythmias are frequently registered during Impella treatment. These include atrial fibrillation (AF, 21.1%) and ventricular tachycardia (VT, 18.3%), as well as AV block II°/III° (AVB, 7.3%), while intermittent asystole (ASY) is the most frequently observed arrhythmia (42.2%). Nevertheless, neither ventricular nor supraventricular tachycardias are associated with patients' survival. In patients who experience intermittent asystole, a trend towards a fatal outcome is noted (p = 0.06). Conclusions: Mortality is high in these severely sick patients. While cardiac arrhythmias were frequent, they did not predict hospital mortality in this population. The hemodynamic support of the pump seems to counterbalance the adverse effects of these events.

Mechanical circulatory support in the management of life-threatening arrhythmia

Life-threatening refractory unstable ventricular arrhythmias in presence of advanced heart failure (HF) may determine haemodynamic impairment. Haemodynamic mechanical support (HMS) in this setting has a relevant role to restore end-organ perfusion. Catheter ablation (CA) of ventricular tachycardia (VT) is effective at achieving rhythm stabilization, allowing patient's weaning from HMS, or bridging to permanent HF treatments. Acute heart decompensation during CA at anaesthesia induction in presence of advanced heart disease, in selected cases requires a preemptive HMS to prevent periprocedure adverse outcomes. Substrate ablation during sinus rhythm (SR) might be an effective strategy of ablation in presence of unstable VTs; however, in a minority of patients, it might have some limitations and might be unfeasible in some settings, including the case of the mechanical induction of several unstable VTs and the absence of ablation targets. In case of the persistent induction of unstable VTs after a previous failure of a substrate-based ablation in SR, a feasible alternative strategy of ablation might be VT activation/entrainment mapping supported by HMS. Multiple devices are available for HMS in the low-output states related to electrical storm and during CA of VT. The choice of the device is not standardized and it is based on the centres' expertise. The aim of this article is to provide an up-to-date review on HMS for the management of life-threatening arrhythmias, in the context of catheter ablation and discussing our approach to manage critical VT patients.

Catheter Ablation in Patients With Cardiogenic Shock and Refractory Ventricular Tachycardia

BACKGROUND

There is paucity of data regarding radiofrequency ablation for ventricular tachycardia (VT) in patients with cardiogenic shock and concomitant VT refractory to antiarrhythmic drugs on mechanical support.

METHODS

Patients undergoing VT ablation at our center were enrolled in a prospectively maintained registry and screened for the current study (2010-2017).

RESULTS

All 21 consecutive patients with cardiogenic shock and concomitant refractory ventricular arrhythmia undergoing bailout ablation due to inability to wean off mechanical support were included. Median age was 61 years, 86% were men, median left ventricular ejection fraction was 20%, 81% had ischemic cardiomyopathy, and PAINESD score was 18±5. The type of mechanical support in place before the procedure was intra-aortic balloon pump in 14 patients (67%), Impella CP in 2, extracorporeal membrane oxygenation in 2, extracorporeal membrane oxygenation and intra-aortic balloon pump in 2, and extracorporeal membrane oxygenation and Impella CP in 1. Endocardial voltage maps showed myocardial scar in 19 patients (90%). The clinical VTs were inducible in 13 patients (62%), whereas 6 patients had premature ventricular contraction-induced ventricular fibrillation/VT (29%), and VT could not be induced in 2 patients (9%). Activation mapping was possible in all 13 with inducible clinical VTs. Substrate modification was performed in 15 patients with scar (79%). After ablation and scar modification, the arrhythmia was noninducible in 19 patients (91%). Seventeen (81%) were eventually weaned off mechanical support successfully, but 6 (29%) died during the index admission from persistent cardiogenic shock. Patients who had ventricular arrhythmia and cardiogenic shock on presentation had a trend toward lower in-hospital mortality compared with those who presented with cardiogenic shock and later developed ventricular arrhythmia.

CONCLUSIONS

Bailout ablation for refractory ventricular arrhythmia in cardiogenic shock allowed successful weaning from mechanical support in a large proportion of patients. Mortality remains high, but the majority of patients were discharged home and survived beyond 1 year.

Mechanical circulatory devices in acute heart failure

PURPOSE OF REVIEW

Temporary circulatory support (TCS) with short-term mechanical circulatory support (MCS) devices is increasingly used as a salvage therapy for patients with refractory cardiogenic shock. This article provides an overview of current devices, their indications and management, and discusses results of recent case series and trials.

RECENT FINDINGS

Percutaneous active MCS devices (Impella, TandemHeart…) and venoarterial extracorporeal membrane oxygenation (VA-ECMO) are utilized as a bridge to 'decision' that includes weaning after cardiac function recovery, transplantation, long-term MCS and withdrawal in case of futility. VA-ECMO is considered the first-line TCS since it allows rapid improvement in oxygenation, is less expensive, and is also suitable for patients with biventricular failure. Combining Impella or intra-aortic balloon pump support with ECMO might decrease left ventricular pressure and improve outcomes. Sepsis-associated cardiomyopathy, massive pulmonary embolism, arrhythmic storm and Takotsubo-like cardiomyopathy are among emerging indications for TCS.

SUMMARY

TCS have become the cornerstone of the management of patients with cardiogenic shock, although the evidence supporting their efficacy is limited. VA-ECMO is considered the first-line option, with a growing number of accepted and emerging indications. Randomized clinical trials are now needed to determine the respective place of different MCS devices in cardiogenic shock treatment strategies.

Electrical storm - still an extremely poor prognosis. Do these acute states of life-threatening arrhythmias require a multidirectional approach from the start?

Electrical storm (ES) is a state of electrical instability of the heart manifesting as multiple and potentially lethal recurring ventricular arrhythmias such as ventricular tachycardia or ventricular fibrillation. This definition is not related to the condition of each patient, who can present from asymptomatic to unconscious and in deep cardiogenic shock. Most patients affected by ES have heart failure (HF) of ischaemic origin. Ischaemia, exacerbation of HF, low ejection fraction, previous ventricular arrhythmias, infection or electrolyte disturbances together with other factors, or a few factors combined, may result in ES. The prognosis of ES survivors is very poor, with 1-year mortality exceeding 40%, which should draw attention to this group of patients as one of extremely high risk. The number of patients with cardioverter-defibrillators is increasing and so is the number of patients suffering from ES. Therefore, each patient should be supported with tailored therapy, and not only restricted to pharmacotherapy or ablation procedures. This paper was written to analyse the most frequent causes of ES and prompt the most appropriate clinical pathways and possibilities, underlining the need for a comprehensive invasive approach to diagnosis, treatment and circulatory stabilization in addition to adequate pharmacotherapy. This approach might help to reduce the mortality rate in this group of patients and improve the prognosis.

Electrical Storm in Patients with Implantable Cardioverter-defibrillators: A Practical Overview

Electrical storm (ES) is an increasingly common medical emergency characterized by clustered episodes of sustained ventricular arrhythmias (VAs) that lead to repeated appropriate implantable cardioverter-defibrillator (ICD) therapies. A diagnosis of ES can be made with the occurrence of three or more sustained episodes of VAs, or of three or more appropriate ICD therapies within 24 hours in patients with implanted devices. ES is associated with poor outcomes in patients with structural heart disease, particularly those with severe left ventricular dysfunction. In large clinical trials involving patients with ICDs for primary and secondary prevention, ES appears to be a predictor of cardiac death, with notably higher rates of mortality soon after the event. ES management is challenging and requires special medical attention with accurate patient risk stratification and a multidisciplinary approach that includes the use of pharmacologic therapies such as antiarrhythmic drugs (AADs) and interventional approaches like catheter ablation, surgical ablation, or sympathetic neuromodulation. Initial management involves determining and addressing the underlying ischemia, any electrolyte imbalances, and/or other causative factors. Hemodynamic support needs to be considered in high-risk patients with unstable VAs or those with severe comorbidities such as low left ventricular ejection fraction, advanced New York Heart Association class, and/or chronic pulmonary disease. Following the acute phase of ES, treatment should shift towards maximizing therapeutic efforts to address heart failure, performing revascularization, and preventing subsequent VAs. In the present manuscript, we offer an overview of the most relevant clinical aspects of ES with regard to novel therapeutic strategies.